Unidentified gunmen have shot dead the head of a Tamil activist group in eastern Sri Lanka, police say.
Vanniasingham Vigneswaran was killed while entering a bank in the eastern city of Trincomalee, they said.
Mr Vigneswaran was the president of the Trincomalee District Tamil People's Forum and is believed to be a supporter of the Tamil Tiger rebels.
In a separate incident, two Muslim guards have been killed in eastern Sri Lanka, police say.
The pro-rebel TamilNet website says Mr Vigneswaran was going to be named as the replacement candidate for a pro-rebel parliamentarian, Joseph Pararajasingham, who was killed last December.
The killing of the two Muslim guards took place at Welikanda some 250km (150 miles) north-east of the capital Colombo, after they completed a night shift.
Following Friday's killings, Norwegian peace envoys said they hoped that both sides would adhere to the ceasefire and take steps to lower the violence.
"All such incidents make the situation more complicated," Norway's International Development Minister, Erik Solheim, told journalists in the Indian capital, Delhi.
Mr Solheim and Norway's special envoy Jon Hanssen-Bauer were briefing Indian officials after their visit to Sri Lanka.
Peace moves
Mr Hanssen-Bauer, who took over from Mr Solheim as Norway's main peace broker in Sri Lanka, will head to London to meet the Tamil Tiger rebel negotiator Anton Balasingham.
On Thursday the Norwegians urged the government and the Tamil Tiger rebels to implement pledges made during recent peace talks in Geneva.
Both sides had agreed to take steps to curb violence following the talks.
The rebels promised to stop attacks on the security forces whereas the government pledged to take necessary steps to act against armed groups that the Tigers say are working with the government security forces against the Tigers.
But Mr Solheim said armed groups hostile to the Tamil Tigers were still being allowed to operate in government-controlled areas.
The Tamil Tigers were also engaged in acts of violence, he said, blaming them for a recent suicide bombing in which eight sailors were lost at sea.
The two sides are due to hold further talks in Geneva later this month.
More than 60,000 people have died during two decades of conflict in Sri Lanka.